Shooting from the hip guys but need some info. For the longest, YS motors, especially 60/61, prior to the AR version (airplane only), had brass sleeves. When the YS 61AR LS came out, they switch to alum. Was this merely for weight saving or some metalurgy reason - heat maybe? If you take a61R LS and a 61AR LS, would the performance be different, say RPM's? Would one out last the other. After running YS motors for the past 27 years, now I ask this question - go figure.

Steven